Ethanol blended gasoline, hurting engine performance, i'm afraid... Options

[saleeka]

This past weekend, I encountered a scenario that got me thinking about ethanol in gasoline again- is it hurting vehicle performance? It all started with a trip over to Wisconsin. On the way home, I had to fill the car up, so I pulled into a station just before I crossed back into MN. I've been filling my car up with premium fuel for quite some time, as I have always felt that it's made a difference in the performance of my car, even more so now that my car has 185,000 miles and has lost a lot of its original power. I noticed that the station I was at had premium fuel that was rated at 91 octane. Typically at home, the station I frequent sells 92, so immediately I thought to myself that I may notice a difference and experience decreased performance. I certainly did not expect it to make the difference that it did. There was a very noticeable improvement in the power that car was putting out! Now that I’ve used up half the tank and have seen that this wasn't a fluke, I started to ask myself why this particular tank of gas was making that difference, and it occurred to me just now.

Here in MN, it's been law for years that all gasoline sold in the state be at least 10% ethanol. After some research, I found that in WI, gasoline that is 91 octane or higher does not have this similar requirement. I then decided to read up on ethanol gasoline blends. I found that for ethanol blends to be used efficiently, the engine burning the blend should have higher fuel injection pressure or larger injectors than that of an engine that runs on gasoline alone, thus explaining why the ethanol-free gas in my car is "creating" more power... Annoying! This is also why only EFI engines can tolerate ethanol blended fuel without re-tuning of various parts of an engine's fuel supply system (cars without electronic oxygen sensors cannot compensate for the difference in energy the fuel contains. I'd also argue that some EFI systems, like our older ones, don't do a good job of adjusting, either. Most vehicles in the USA can only tolerate up to a 90/10 % split without big problems). More discouraging facts: ethanol blends have larger amounts of water in them compared to gasoline, and they also contribute to accelerated engine wear thanks to the "drying" effect alcohol has...

All this info makes me suspect that my car isn't as tired and worn out as I once thought. I'm now thinking it's the gas blends we are required to use in this state. For those of you who have easy access to ethanol-free gasoline, I'd strongly recommend selecting that choice over the blend.

[hasty]

Well i don't know about ethanol but if you have eropean or jdm engine then it's totally understandable that your car runs better with higher octane since they arent designed for US low octane your max octane is minium here in europe so no wonder if DEATHs jdm 3sgte runs better because i recall that japan has same octanes as europe, but if you'd compare 95(your 91) wich is minium here and max 100octane there's no difference.

So in other words if you have 5s i belive your mind made a tricks with you but if that's 3s then you're most likelly right and your car is running better.